Providing uniform vapor distribution in high capacity fractionation towers is one of the most challenging aspects of designing a high performance column. Conventional devices within the industry have attempted to evenly distribute the inlet feed gas to the section directly above the feed nozzle in MF columns. For example, the Vapor Horn and the Schoepentoeter, are proprietary vapor inlet horn and vane type inlet devices, respectively, which introduce gas/liquid mixtures into a vessel or column. However, these devices proved to be problematic because as the feed gas cools inside both devices, the heaviest components, e.g., asphaltenes, start condensing and deposit or stick to the cool surfaces of the apparatus. With further and continuous contact of the hot feed gas there is stripping of the lighter material from the deposit, as well as stripping of hydrogen atoms from the polymerized asphaltenes causing it to turn to coke. With time, the coke deposit grows to significant size and caused interference with the flow of gas and, as a result, the devices have to be taken out of the MF columns.
Typical prior art devices that have tried to address the problem of ensuring good mixing and even distribution are disclosed in the following: U.S. Pat. No. 8,286,952 to Lee et al. discloses a vapor distributor for gas-liquid contacting column; U.S. Pat. No. 8,025,718 to Kooijman et al. discloses a Fluid Inlet Device; U.S. Pat. No. 7,744,067 to Kurukchi et al. discloses a three phase vapor distributor; U.S. Pat. No. 7,459,001 to Christiansen et al. discloses a vane diffuser; U.S. Pat. No. 7,281,702 to Jacobs et al. discloses methods and an apparatus for mixing and distributing fluids; U.S. Pat. No. 7,104,529 to Laird et al. describes a vapor distributor apparatus, the vapor horn of which includes a series of vanes the sizes of which increase with distance from the inlet nozzle of the vapor distributor; U.S. Pat. No. 6,997,445 discloses a method and device for introducing a liquid-vapor mixture into a radial feed cylindrical fractionating column; U.S. Pat. No. 6,948,705 to Lee et al. describes a gas-liquid contacting apparatus in which a gas stream, for example steam, is fed into a column via an annular vapor horn; U.S. Pat. No. 6,889,961 to Laird et al. described a modified vapor distributor with baffles in the lower intermediate transitional section to reduce swirling of the feed and thereby improve distribution; U.S. Pat. No. 6,889,962 to Laird et al. disclosed an annular inlet vapor horn that circulates the inlet feed so as to de-entrain any liquid droplets while providing for more even distribution of the inlet flow across the column; U.S. Pat. No. 6,309,553 to Lanting et al. discloses a phase separator having multiple separation units, upflow reactor apparatus, and methods for phase separation; U.S. Pat. No. 6,341,765 to Moser discloses a method for the infeed of a fluid into an apparatus; U.S. Pat. No. 5,632,933 to Yeoman et al. describes an annular bi-directional gas flow device having a plurality of outlets at an inner wall of the housing and a series of flow directing vanes for distribution of an inlet vapor stream across the breadth of a column; U.S. Pat. No. 5,605,654 to Hsieh et al. disclosing a vapor distributor having an annular housing with a series of ports for feeding the vapor stream in a distributed manner; U.S. Pat. No. 5,558,818 to Gohara et al. discloses a wet flue gas scrubber having an evenly distributed flue gas inlet; U.S. Pat. No. 5,632,933 to Yeoman discloses a method and apparatus for vapor distribution in mass transfer and heat exchange columns; U.S. Pat. No. 5,106,544 to Lee et al., which describe a combination of an inlet horn having a 360 degree annular housing with directional flow vanes; U.S. Pat. No. 4,435,196 to Pielkenrood discloses a multiphase separator for treating mixtures of immiscible gaseous, liquid and/or solid components, comprising a gas-tight and pressure-proof tank; U.S. Pat. No. 3,651,619 to Miura discloses an apparatus for the purification of gas; and U.S. Pat. No. 3,348,364 to Henby discloses a gas scrubber with a liquid separator.
Some other prior art devices that have tried to address the above-referenced problems include the following: U.S. Published Application 2005/0146062 to Laird et al. discloses a method and apparatus for facilitating uniform vapor distribution in mass transfer and heat exchange columns; U.S. Published Application 2005/0029686 to Laird et al. discloses a fluid stream feed device for a mass transfer column; and U.S. Published Application 2003/0188851 to Laird et al. discloses a method and apparatus for uniform distribution in mass transfer and heat exchange columns.
Additional prior art references in this regard include: McPherson, L. J.: “Causes of FCC Reactor Coke Deposits Identified”; O&GJ, Sep. 10, 1984, pp 1 39; NPRA Question and Answer Session, 1986, (Transcripts) Heavy Oil Processing, Question 12, pp 45; Lieberman, N. P.: “Shot Coke: its origins and prevention”: O&GJ, Jul. 8, 1985. pp 45; Christopher Dean et. al. “FCC Reactor Vapor Line Coking,” Petroleum Technology Quarterly Autumn 2003; Christopher Dean et. al. “Process Equipment Specification and Selection,” Petroleum Technology Quarterly Autumn 2004; Hanson D. W. et. al. “De-Entrainment and Washing of Flash-Zone Vapor in Heavy Oil Fractionators,” HCP, July 1999, 55-60; Scott W. Golden et. al. “Correcting Design Errors can Prevent Coking in Main Fractionators,” Oil & Gas J. Nov. 21, 1994, 72-82; Dana G. Laird. “Benefit of Revamping a Main Fractionator,” Petroleum Technology Quarterly; Winter 2005. David Hunt et. al.; “Minimizing FCC Slurry Exchanger Fouling,” Petroleum Technology Quarterly Winter 2008; Mark Pilling et. al.; “Entrainment Issues in vacuum Column Flash Zones,” Petroleum Technology Quarterly; Winter 2010.
It is worth noting that in the majority of devices utilizing a vapor horn the inlet flow is unidirectional with a cyclonic effect on the vapor feed. In these types of devices, baffles or vanes are used to redirect or disrupt the circular flow of the inlet stream.
As such, it would represent an advancement in the state of the art and resolve a long felt need in the art if a gas distributor device that could cool the high velocity superheated feed gas to the MF column and distribute it evenly to the bottom of the slurry packed section without fouling and coke deposition inside the feed distributor device.